Loading, and dynamically reloading, multiple river files

[nigelsim]

I have Grafana Agent running as a container, where other containers are managed by configuration management (Salt in this case, but it isn't important). Currently, all the basics (node exporter, cadvisor, and docker logs) are working, but I want to allow individual containers to export custom metrics.

The question is, how do I get Grafana Agent to dynamically read in metrics-*.river files? Much the same as what the dynamic configuration metric_instance-*.yml would do.

#2560 looks like it is asking the same question, but the suggested answer of module.loader.array doesn't seem to exist, and it doesn't seem possible to "template" the river files to create module.file entry per file in discovery.file